In recent years, interest has emerged in diapers of the type commonly referred to as “training-pants”. When this product is extracted from the packaging it has a conformation essentially similar to that of a pair of pants. It is worn by sliding it on the legs of the user according to criteria essentially similar to those used for wearing pants.
Training-pants typically include a central body comprising an absorbent core and side panels which extend laterally from the central body so as to complete the pant-type shape of the product. The side panels are fitted with homologous distal edges designed to be connected (pre-fastened) to one another to form fastening regions.
In the most recent products, the pre-fastened fastening regions are openable and closeable, thus allowing the product—sold in a closed pant condition—to be selectively opened on each side.
A technique for the manufacture of pant-type absorbent products envisages the manufacture of discrete flat products that advance in a continuous manner along a direction parallel to the longitudinal direction of the products. The discrete products are then subjected to a folding operation about an axis transverse to the longitudinal axis of the products.
The document U.S. Pat. No. 6,514,187 describes a method and an apparatus for the transverse folding of absorbent products. In the solution described in this document the homologous side panels are maintained separate from each other during the folding operation. The mutual coupling of the side fastenings for closing the product is carried out in a subsequent stage of the manufacture cycle, for example as described in the document U.S. Pat. No. 6,513,221.
Other documents such as U.S. Pat. No. 7,322,925; U.S. Pat. No. 7,335,150, U.S. Pat. No. 7,387,148, EP-A-1289465, EP-A-2289466, EP-A-1284700 describe methods and equipment that can be applied for the manufacture of absorbent products with refastenable side fastenings.
A known solution envisages the inward folding of the side panels, arranged with respective fastening elements facing each other. In this way, when the article is folded transversely, the opposing fastening elements are pressed against each other so as to provide the pre-fastened configuration of the absorbent article.
The document U.S. Pat. No. 8,221,378 describes a solution wherein the folded portions of the side panels are held by temporary releasable welds, having a peel strength less than the peel strength of the refastenable fastening elements of the side panels.
This solution suffers from curious drawbacks. Indeed, the temporary welding that retains the folded portions of the side panels limits the choice of materials usable for the side panels to easily-weldable materials that are compatible with each other. The temporary welding may also ruin the material and produce lacerations in the case in which it has a peel strength greater than the peel strength between the refastenable fastening elements of the side panels. In the case in which the temporary welding has too weak a peel strength, the temporary connection between the folded portions of the side panels could open during the manufacturing method, causing release of the side panels and the non-fastening of the side panels during the transverse folding of the articles.